JSF 1.1 VariableResolver that first delegates to the
original resolver of the underlying JSF implementation (for resolving
managed-bean objects as defined in faces-config.xml
as well as well-known implicit EL attributes), then to the Spring
root WebApplicationContext (for resolving Spring beans).

getBeanFactory

The default implementation delegates to getWebApplicationContext.
Can be overridden to provide an arbitrary BeanFactory reference to resolve
against; usually, this will be a full Spring ApplicationContext.